From 95d2eb95c303f859adb9d3b19ecce056e539f61d Mon Sep 17 00:00:00 2001 From: Jim Grosbach Date: Wed, 6 Mar 2013 05:44:53 +0000 Subject: InstCombine: Don't shrink allocas when combining with a bitcast. When considering folding a bitcast of an alloca into the alloca itself, make sure we don't shrink the amount of memory being allocated, or things rapidly go sideways. rdar://13324424 llvm-svn: 176547 --- llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'llvm/lib/Transforms') diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp index a960ab2499c..d162223a6f5 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp @@ -104,6 +104,12 @@ Instruction *InstCombiner::PromoteCastOfAllocation(BitCastInst &CI, uint64_t CastElTySize = TD->getTypeAllocSize(CastElTy); if (CastElTySize == 0 || AllocElTySize == 0) return 0; + // If the allocation has multiple uses, only promote it if we're not + // shrinking the amount of memory being allocated. + uint64_t AllocElTyStoreSize = TD->getTypeStoreSize(AllocElTy); + uint64_t CastElTyStoreSize = TD->getTypeStoreSize(CastElTy); + if (!AI.hasOneUse() && CastElTyStoreSize < AllocElTyStoreSize) return 0; + // See if we can satisfy the modulus by pulling a scale out of the array // size argument. unsigned ArraySizeScale; -- cgit v1.2.3